title: A decreased micronucleus frequency in human lymphocytes after folate and vitamin B12 intervention: a preliminary study in a Yunnan population.
abstract: BACKGROUND
  Micronucleus (MN) is a validated biomarker for DNA damage in peripheral blood lymphocytes (PBL) and is a reflection of the changes of human nutritional status. Folate (FA) and vitamin B(12) are one-carbon metabolism-related micronutrients, which play important roles in maintaining genomic stability.
  
  
  OBJECTIVE
  To investigate the correcting effects of FA and B(12) intervention on DNA damage in PBL.
  
  
  METHODS
  One hundred fifty-six volunteers without history of cancer were divided into 5 age groups (20 - 69 y, 47.4 % male) for establishing the baseline of chromosomal damage by means of cytokinesis-block micronucleus assay. Twelve individuals whose MN frequency was higher than the median value in each age group were selected for a four-month FA (200 - 400 μg/day)-B12 (3.125 - 25 μg/day) intervention dosed as to age and MTHFR genotypes.
  
  
  RESULTS
  There were significantly positive correlations between age and MN frequency in all groups (p < 0.01). Among all age groups, the baseline MN frequencies were higher in females than that in males. The MN frequencies from 10 volunteers were reduced by 33.5 % after the intervention with the two micronutrients (p < 0.01), and two individuals did not show any changes.
  
  
  CONCLUSIONS
  Dietary supplement intake of FA and B(12) based on MTHFR genotypes could protect the genome from damage and benefit genome health.
authors.affiliation: School of Life Sciences, Yunnan Normal University, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming, Yunnan, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Ni
authors.forename: Ziqing
authors.initials: Z
authors.lastname: Liang
authors.forename: Tao
authors.initials: T
authors.lastname: Zhou
authors.forename: Neng
authors.initials: N
authors.lastname: Cao
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Xia
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D005838:Genotype; D006801:Humans; D008214:Lymphocytes / Q000648:ultrastructure*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D048629:Micronuclei, Chromosome-Defective; D008875:Middle Aged; D014805:Vitamin B 12 / Q000008:administration & dosage*
chemical_list: D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12